Alpha Muscae
 Location of ε Muscae (circled) |
|
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Musca |
| Right ascension | 12h 37m 11.01789s[1] |
| Declination | –69° 08′ 08.0332″[1] |
| Apparent magnitude (V) | +2.69[2] |
| Characteristics | |
| Spectral type | B2 IV–V[3] |
| U−B color index | −0.854[2] |
| B−V color index | −0.219[2] |
| Variable type | β Cep[4] |
| Astrometry | |
| Radial velocity (Rv) | +13[5] km/s |
| Proper motion (μ) | RA: −40.20[1] mas/yr Dec.: −12.80[1] mas/yr |
| Parallax (π) | 10.34 ± 0.11[1] mas |
| Distance | 315 ± 3 ly (97 ± 1 pc) |
| Absolute magnitude (MV) | –2.2[6] |
| Details | |
| Mass | 8.8 ± 0.1[3] M☉ |
| Radius | 4.8[7] R☉ |
| Luminosity | 4,000[6] L☉ |
| Surface gravity (log g) | 4.06[6] |
| Temperature | 21,400[6] K |
| Rotational velocity (v sin i) | 114[8] km/s |
| Age | 18.3 ± 3.2[3] Myr |
| Other designations | |
Alpha Muscae (α Muscae, α Mus) is a star in the southern circumpolar constellation of Musca. With an apparent visual magnitude of +2.7,[2] it is the brightest star in the constellation. The distance to this star has been determined using parallax measurements, giving an estimate of about 315 light-years (97 parsecs) from Earth.[1]
With a stellar classification of B2 IV-V,[3] this star appears to be in the process of evolving away from the main sequence of stars like the Sun and turning a subgiant star, as the supply of hydrogen at its core becomes exhausted. It is larger than the Sun, with nearly nine[3] times the mass and almost five[7] times the radius. This star is radiating around 4,000[6] times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 21,400 K,[6] giving it the blue-white hue of a B-type star.[10]
Alpha Muscae appears to be a Beta Cephei variable star. Telting et al. (2006) report it as a Beta Cephei with a high degree of confidence,[4] although Stankov and Handler (2005) listed it as a poor or rejected candidate in their Catalog of Galactic β Cephei Stars.[8] It is rotating rapidly with a projected rotational velocity of 114 km s–1[8] and has an estimated age of about 18 million years.[3]
This star is a proper motion member of the Lower-Centaurus Crux sub-group in the Scorpius-Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.[6] Alpha Muscae has a peculiar velocity of 10 km s−1, which, while high, is not enough for it to be considered a runaway star.[3]
References [edit]
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357
- ^ a b c d Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168
- ^ a b c d e f g Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x
- ^ a b Telting, J. H. et al. (June 2006), "A high-resolution spectroscopy survey of β Cephei pulsations in bright stars", Astronomy and Astrophysics 452 (3): 945–953, Bibcode:2006A&A...452..945T, doi:10.1051/0004-6361:20054730
- ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E
- ^ a b c d e f g de Geus, P. T.; de Zeeuw; Lub, J. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", Astronomy and Astrophysics 216 (1-2): 44–61, Bibcode:1989A&A...216...44D
- ^ a b Underhill, A. B. et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society 189: 601–605, Bibcode:1979MNRAS.189..601U
- ^ a b c Stankov, Anamarija; Handler, Gerald (June 2005), "Catalog of Galactic β Cephei Stars", The Astrophysical Journal Supplement Series 158 (2): 193–216, arXiv:astro-ph/0506495, Bibcode:2005ApJS..158..193S, doi:10.1086/429408
- ^ "HD 109668 -- Variable Star of Beta Cep type", SIMBAD Astronomical Database, retrieved 2007-01-29
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16
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